Pneumatic cushioning seat support with variable cushioning and snubbing diaphragm action



United States Patent Oilice Patented Fel). 15, 1966 3,235,221 PNEUMATIC CUSHIONING SEAT SUPPORT WITH VARIABLE CUSHNING AND SNUEBING DIA- PHRAGM ACTIN Lyman Clark Conner, Los Angeles, Calif., assigner to Flexible-Air Seat Corporation, Los Angeles, Calif., a corporation of California Filed .lune 12, 1964, Ser. No. 374,572 6 Claims. (Cl. 24S- 400) This invention relates to diaphragm type pneumatic seat supports of the type disclosed in my Patent No. 2,880,782 issued April 7, 1959, and has as its general object to provide a seat support of that general type with improved variable cushioning action.

Hitherto, seat supports of this type have embodied a combination of a cylindrical dome-shaped diaphragm and a housing of generally corresponding cylindrical domeshape fitted closely to the cylindrical lateral wall of the diaphragm. While such seat supports provide pneumatic cushioning action, such action is characterized by a rapid increase in the resistance to downward loads and also by noticeable rebound. In the existing seat supports of this general type, the seat is supported upon a cylindrical column which slides vertically in the top of the pneumatic housing and is Iattached to the top of the diaphragm. Means is necessarily provided to restrain the seat against rotation about the axis of this column so as to maintain the seat oriented in a forwardly-facing direction, such means being in the nature of a vertically slidable guide means. Also, in such seat supports, a pneumatic snubhing chamber is provided between the top of the diaphragm and the top of the housing land pneumatic snubbing of rebound is attained by restricted breathing of air through the top of the housing between said snubbing chamber and atmosphere. With the general object of improving the operation of this type of seat support, the invention aims to provide a pneumatic cushioning app-aratus wherein:

(1) Road shocks directed upwardly from the vehicle to the seat are initially absorbed by a soft cushioning action;

(2) Minor shocks and vibrations are completely ab- .sorbed in the soft cushioning action;

(t3) Cushioning air volume is increased over that of the existing seat supports of this type without increase of .the overall envelope dimensions of the unit;

(4) Rebound is minimized;

(5) Rebound is absorbed with a variable snubbing action of a softer character than in the earlier seat supports of this general type;

(6) There is provided improved and simplified means for controlling the air in the snubbing chamber for control of snubbing action;

(7) The seat-supporting column is restrained against rotation by vertically slidable guide means of improved and simplified construction.

Other objects and advantages will become apparent in the ensuing specification and appended drawing in which:

FlG. 1 is a perspective view of a pneumatic seat support `embodying the invention;

FIG. 2 is a vertical sectional view thereof;

FIG. 3 is a fragmentary detail sectional view representing an enlarged portion of FIG. 2 embodying the improved guide mechanism;

FIG. 4 is a detail fragmentary sectional view illustrating the snub-hing control valve; and

FIG. 5 is a detail fragmentary sectional view illustrating a modied form of the invention.

Referring now to the drawing in detail, I have shown therein, as an example of one specic form in which the CII invention may be embodied, a seat support comprising, in general, an assembly of generally circular parts, coaxial on a vertical axis, comprising, in general, a base plate A; a rigid housing B and a flexible diaphragm C, both of dome shape and both secured and sealed to the base plate A at their lower ends; a guide spindle D secured to the center of the base plate A and projecting upwardly through the center of its top; a tubular seat support column E slidable vertically upon the spindle D and through the top of housing B and in supporting relation to a seat F secured to its upper end; a guide collar and snubber control assembly G closing the top of housing B; and inflation means H for injecting air under pressure into a cushioning chamber I which is delned between the base plate A and the diaphragm C; a snubbing chamber J being defined between the top of diaphragm C and the top of housing B. The apparatus also includes rotation-preventing guide means K.

Base plate A comprises a body 10 of flat, circular disc form having peripheral apertures 11 for anchor bolts to secure the unit to a supporting floor. Apertures 11 may be optionally embodied in integral ears 12 projecting radially from the periphery of body 10. A shallow circular groove is provided in the upper face of body 10 near its periphery, providing a seat 13 for receiving the lower end of diaphragm C in conned relation. In a central boss 14 there is provided an internally threaded vertical bore to receive the lower end of spindle D. In one side of base plate A is a horizontal passage 1S extending radially from a vertical, upwardly extending inlet port 16 formed in an integral ear 17. The passage 15 extends beneath and inwardly beyond the diaphragm seat 13 and terminates in an outlet port 18 extending vertically upwardly and communicating with the cushioning chamber I.

Spindle D is a rigid cylindrical member 21 which may optionally be solid or tubular but in either event =functions as a closure (as iby means of a closed upper end 22) for au upper snubbing chamber 23 dened between it and the upper end of seat column E. Spindle D is sealed within column E sufficiently to generate a vacuum in chamber 23 in response to any rebound movement of column E above its normal rest position, thus snubbing such rebound.

Housing B consists of a rigid shell of a material having suitable characteristics of rigidity, toughness to withstand the pneumatic pressure loads, shock, vibration, aging etc., sutiiciently air impervious to maintain the pneumatic snubbing action in chamber l, and suiiciently strong to withstand the pressure loads transferred to it by diaphragm C during cushioning and snubbing actions.. As an improved feature in the present invention, .housing B is fabricated by spinning it of sheet aluminum alloy or sheet steel within a sectional `female mold which imparts its designed contours to it. In general, housing B comprises a base flange 31, a skirt 32 rising therefrom and a top 33 having a circular central aperture in which the guide and snubbing control collar assembly G is mounted.

The major improvement of the present invention is attained by a novel cross sectional configuration in the skirt 32 of the housing, departing from the plain cylindrical form of the housing in the earlier seat supports of this type. From the at base flange 31, a short rim portion 34 extends upwardly substantially at` the outer diameter of the generally cylindrical lateral wall of diaphragm C and in encircling, laterally supporting relation thereto (eg. in actual engagement with, or only slightly spaced from the diaphragm wall in the normal loading thereof by the dead weight of the seat F and its occupant). ALbove the rim portion 34, the shirt 32 has a. toroidal outwardly` bulged wall portion 35 which is normally spaced outwardly from the lateral wall of diaphragm C so as to define an annular expansion chamber 36 surrounding the diaphragm C and into which it is expanded during cushioning action. At its upper end, the bulged skirt portion converges back to the diameter of diaphragm C and substantially meets the periphery of the top thereof. At this level, through a reversely curved zonal bend 37, the bulged skirt portion 35 is joined to an .annular peripheral dome portion 38 which terminates in a reentrant seat 39 of generally flat ring form the inner edge of which defines the central circular aperture in the housing top 53. The seat 39 is depressed below the annular dome portion 33 so as to generally parallel the reentrant, depressed central portion of the diaphragm C as hereinafter destribed, and provides a mounting for the collar assemby G.

Diaphragm Cl comprises generally a substantially flat base flange 41 projecting radially outwardly from a skirt 4Z which rises therefrom, and a top portion 43 which is spaced below the housing top 33 to define the annular snuober chamber J. The skirt 42 has a cross sectional configuration such as to provide radial clearance between itself and the bulged housing wall 35 which provides for the ballooning of the diaphragm wall 42 into contact with the bulged skirt 35 with a progressive increase in the area of contact accompanied by a progressive stifening of the resistant provided by the pneumatic cushioning action in chamber I, as hereinafter described more in detail. For best results, the radial spacing between diaphragm wall 42 and housing wall 35 in the annular expansion chamber 36 is graduated from a maximum in a vertically intermediate zone thereof to minimums at the upper and lower extremities of expansion chamber 36, which minimums are such as to approach actual normal contact between the diaphragm and the housing in zones near the lower end thereof and the upper peripheral portion 44 of diaphragm skirt 42 where it joins its top 43. I have found that excellent results are obtained where the diaphragm skirt 42 is cylindrical as in the earlier seat supports of this type and wherein the graduated radial clearance in chamber 36 is provided for entirely by the bulge in lateral housing wall 35. However, the invention is not restricted to the cylindrical shape of diaphragm wall 42 but contemplates modifications as shown in FIGS. 5 and 6, described hereinafter.

Diaphragm top 43, adjacent the upper extremity 44 of skirt 42, embodies a thickened portion including a peripheral bead 45 which stiffens the periphery of top 43, resisting inward contraction thereof and thus providing an element of soft resistance to initial deformation of the diaphragm from its normally loaded condition. The thickening of the diaphragm wall may extend into the upper end 44 of skirt 42, inwardly into a crown corrugation 45 constituting the upper extremity of top 43, and thence into an intermediate corrugation 46. A lower corrugation 47, continued inwardly from corrugation 46, cooperates with the latter in providing a stretchable central portion of diaphragm 43 which provides for initial downward yield against the air cushion in chamber I during which the corrugations 46, 47 undergo some flattening while the thickened rim 44, 45 offers resistance to inward contraction. Corrugation 47 also defines the peripheral wall of a central cup having a flat bottom against which the base of support column E is seated. The diaphragm is secured by means of a at clamp washer 49 and cap screws 50 extending through the washer 49 and through the central cup bottom and threaded into the base of support column E. The central cup bottom, being of compressible material (e.g. rubber or synthetic elastomer) and being under compression between washer 49 and the base at column E, it seals the top of cushion chamber I. Similarly, the base flange 41 of diaphragm C functions as a gasket to seal the base of housing B to base plate 1f).

Support column E, which is preferably of metal although it can be of any equivalent material (eg. plastic resin) having comparable characteristics of rigidity, toughness and resistance to vibration and deterioration, comprises a cylindrical tube 51 having a closed upper end 52 providing a flat seat, normal to its major axis, to which a seat support pad 53 (which can be a fiat plate as shown) is secured by any suitable means such as cap screws 54. At its lower end, column E has a radially outwardly projecting at base flange 55 which is sealed to the diaphragm top 43 by O-ring 59, and secured by cap screws 5t), as previously described. O-ring 59 is received in an annular groove in the base fiange 55. A second annular groove 58 in flange 55 is effective to contain the inward marginal portion of flange 48, preventing it from being extruded into column E.

Tube 51 has in its lower poriton a counterbore in which is snugly seated a nylon bearing sleeve 56 `the inner wall of which has a smooth sliding fit around a smoothly finished cylindrical external surface of spindle D, providing substantially a pneumatic seat there-with such as to provide cushioning action in top snubbing chamber 23. Sleeve 56 may be of nylon or T efon or any equivalent bearing material of long life, low friction characteristics.

Guide collar and valve assembly G comprises a collar body 61 having suitable internal annular grooves and intervening ribs interlocked with a grooved and ribbed exterior of a bearing bushing 62 (FIG. 3) which is thereby Isecurely mounted therein; having a lower internal annular groove receiving and supporting an O-ring 63 which pneumatically seals the collar .to a smoothly finished cylindrical external sur-face of support tube 5l; and having a radial flange 64 which lis mounted upon the central seat portion 39 of housing top 33, secured thereto by suitable means such as bolts 65, and pneumatica'lly sealed thereto by suitable sealing means (not shown).

Extending vertically through collar body 61, parallel to its axis, is an air inlet port 66. In the port 66 is a check valve 6'7 which permits unrestricted inward flow of air into snubbing chamber J but prevents outward flow through port 66.

A restricted outlet port 68 (FIG. 4) extending vertically through collar body 61 at a position circumferentially spaced from inlet port 66, is controlled by a needle valve 69 so as -to adjustably restrict the outflow of air from snubbing chamber I during a return of diaphragm C to its normally loaded condition, thereby provi-ding variable control of the snubbing action in main snubbing chamber I.

Inflation mechanism H may consist of a pair of Schrader valves 71 and 72 connected by a common stem to inlet port 16 of base plate A and adapted to be selectively coupled to a tire pump or other means for pumping air into cushion chamber I through inlet passage 15 so as `to provide an air cushion having a pressure selected to meet the requirements or desires of a particular user.

Seat guide K comprises a smooth cylindrical rod 81 having its upper end received in an aperture in support pad 53 and suitably secured therein as by nuts 82 threaded thereon and having its intermediate portion slidably extended through a bearing bushing 83 (FIG. 3) mounted in a bore 84 extending vertically through collar body 61. Bushing 83 is of a long-wear, low-friction material such as nylon or Teon or equivalent. Guide rod 81 is pneumatically sealed to the collar by an O-ring 85 mounted in an annular groove in the collar at the lower end of bore 84. The lower end of rod 81 is threaded or pressed into the base flange 55 of support column E. Thus, while pneumatically sealed in the collar assembly G, guide rod 81 prevents rotation of the column E with reference to the housing B without resisting the vertically sliding movement of column E.

Modified forms-FIGS. 5, 6. The invention contemplates the possibility of having some lateral, outward bulge in the diaphragm skirt, as at 42a in FIG. 5 (in which case the housing lateral wall 35a may have a somewhat greater extent of lateral bulge than in FIG. 2).

Operation In the operation of the apparatus, minor road shocks and vibrations, transmitted upwardly from the vehicle floor to base plate A, will be opposed by the inertia of the dead weight of the seat and the driver therein tending to move the support column E downwardly with reference ,to the housing B, followed by return movements in which column E will move upwardly rela-tive to the housing. Although the movements are only relative (an actual movement may langely consist of an upward movement of the vehicle floor and the housing B with reference .to support column E) the oper-ation can best be explained in connection with the drawings by referring to the relative movements of support column E, and to avoid repetitions application of the adjective relative to directions of these relative movements are hereinafter named unqualifiedly, but it should be understood that in each instance the direction is to be understood as being relative.

In absorbing minor road shocks and vibrations, and in the initial phases of absorption of heavier shocks, the downward movements of support columnE will rst distend the corrugated mid portion of diaphragm top 43 against the resistance or the thickened peripheral top portion 44, 45 of the diaphragm to being contracted inwardly. In this early stage of downward movement, the diaphragm top d3 will move toward an intermediately depressed position approximately as indicated at 43 in FIG. 2, eliminating a very substantial decrease in the actual volume of chamber I, and some corresponding increase in pressure therein, but these increases will be quite moderate for the reason that the expansion chamber 36 provides minimal resistance to outward ballooning of the thin, highly tiexible skirt 42 of the diaphragm, and in this initial stage of deection, the decrease in volume at the top is largely offset by expansion of volume at the side. Accordingly, the cushioning action in this initial stage has only a minor pneumatic component and is largely derived from the inherent resistance to deformation of the diaphragm top 43. Thus, there is provided a soft cushioning action which will absorb minor road shocks and vibrations with maximum yieldability.

When the support column E has moved downwardly to the intermediate position indicated at S5', and the diaphragm top has gone through the intermediate distention stage, attaining the condition of distention indicated approximately at 43', an attendant ballooning of diaphragm skirt 42 to a distended position approximately as indicated at 42 will have occurred, in which the upper portion of the distended skirt 42.' will be pressed firmly against the upper portion of the bulged housing skirt 42, thus partially restricting further ballooning action. In further downward movement of support column E to the position indicated at 55", substantially maximum flattening of corrugations 46, 47 will have occurred, substantial tension will be developed in the diaphragm top 43 at 43", the volume in the upper and central area of chamber I will be further reduced so as to substantially reduce the actual volume of chamber I with a corresponding substantial increase in pneumatic pressure, and diaphragm skirt 42 will have been ballooned into full contact with the lower portion of bulged housing skirt 35 as indicated in 42". Because of the increasing restriction of the expansion chamber 36 and the increasing area of full contact between the diaphragm skirt 42 and housing bulge 35, will be a gradually increasing stiffness in the cushioning action. At the point where the ballooning diaphragm skirt has completely traversed the expansion chamber and has established full contact with housing bulge 3S, the partial odsetting of the decrease in volume of chamber I at top center by expansion at the side will be arrested, and further downward movement of support column E, drawing diaphragm top 43 further downwardly into chamber I, will be resisted by sharply increased pneumatic cushioning. The relatively gradual increase in compression in cham- 6 ber I will thereafter become a rapid increase to relative high pressure which will provide a rm pneumatic bottoming action suficient to prevent impact of the lower end of support column E against the base plate A.

The volume of expansion chamber 36 is added to the aggregate volume of the cylindrical housing of the earlier pneumatic support, and this additional volume is added to the effective volume of chamber A in the manner described above. Thus the increased volume of the cushioning chamber in itself adds to the aggregate improvement in cushioning, over and above the improved cushioning operation described above.

The increase in pressure in air within the bag when it is fully compressed and its sidewalls distended, will be fully dissipated on the return movement when the bulged wall returns to its normal cylindrical shape, and beyond that point there will be no force effective to cause rebound. Any tendency to rebound above the rest position will be opposed by the resistance of the relatively stiff top section of diaphragm C to being distended upwardly. The air movement during the return of the diaphragm to its normal cylindrical shape will be a radially inwardly directed movement and will likewise be dissipated when the diaphragm returns to its normal shape.

Due to the fact that the volume of the snubbing charnber is in effect increased (over that of the earlier type) by an amount equal to a substantial portion of the volume of the expansion chamber 36, and relatively light resistance to the rebound will be offered by the compression of air in the rebound chamber (the entire area above the diaphragm at the 43 position) until the upper end 44 of the diaphragm skirt has reestablished substantial contact with the housing at level 37. Since the diameter of the housing is considerably less above this level than in the outwardly bulged area of the skirt 35 below, the volume of the snubbing chamber will be very sharply reduced in the upward transition of diaphragm top 43 past the level 37, and there will be a rapid rise in pneumatic snubbing action in the movement of the diaphragm topto this level from a position just below it, corresponding approximately to the position indicated at 43. Further upward movement of diaphragm top 43 above the level 37 will develop sharply increasing compression in snubbing chamber J accompanied by a rapid stifening of the snubbing action such as to completely absorb the rebound so as to prevent impact of the base ange of support column E against collar assembly G.

I claim:

I. A pneumatic cushioning support comprising: a housing having a base, a skirt rising from said base and a top defining a central opening; a guide collar on said top around said opening; a seat support column slidable vertically in said collar and guided thereby; and a dome-shaped diaphragm having a lower end sealed to said base, a generally cylindrical skirt rising therefrom within said housing, and a top adjacent the top of said housing and having a central portion supporting said column; a pneumatic cushioning chamber being defined within said diaphragm between its top and said base; said skirts having radially opposed portions thereof at their upper and lower extremities substantially in contact with one another and said housing skirt having an annular portion thereof intermediate its said upper and lower end portions bulged radially away from the opposed intermediate portion of the diaphragm skirt in the normally loaded condition of the diaphragm and dening therewith an annular expansion space into which the diaphragm skirt is distended during relative downward movement of the diaphragm top into said cushioning chamber, the parts being so proportioned that the diaphragm skirt will be distended into full contact with the housing skirt below the diaphragm top and there will be a resultant rapid increase in air-cushion resistance to said downward movment, at a level of said downward movement sufficiently above said base to provide a pneumatic bottoming action absorbing heavy road shocks.

2. A cushioning support as defined in claim 1, wherein a pneumatic snubbing chamber is dened between the top of said diaphragm and the top of said housing, the volume of said snubbing chamber being increased by a substantial portion of the volume of said expansion chamber in the position of said pneumatic bottoming of the diaphragm top, whereby to provide an improved gradual pneumatic snubbing action in the rebound from said bottoming position, and wherein said diaphragm skirt at its upper end will establish substantial closing contact with said housing skirt at a level just below the normally loaded position of the diaphragm top and wherein the diameter of said snubbing chamber above said level is substantially reduced below that of said expansion chamber whereby, in upward rebound movement of the diaphragm top above said level, a rapid increase in compression in said snubbing chamber will occur, for final absorption of rebound without contact of the upwardly moving parts against the housing top.

3. A cushioning support as defined in claim 2, including, in said collar, an inlet for said snubbing chamber provided with a check valve permitting unimpeded inow into said snubbing chamber but preventing oullow therefrom, and including in said collar an outlet port and a manually adjustable valve for providing variable restriction in said outlet port to the outllow of air from said snubbing chamber.

4. A cushioning support as delined in claim ll, wherein said proportioning is such that said pneumatic bottoming action will completely absorb heavy road shocks without impact of the downwardly moving parts against said base.

5. A cushioning support as deined in claim 1, wherein said housing skirt and diaphragm skirt have respective radially opposed outwardly bulged sections between their upper and lower extremities and wherein said housing skirt has a greater outward bulge than said diaphragm skirt so as to define between said bulged sections said expansion chamber of gradually decreasing radial clearance between said bulge sections from the medial horizontal plane thereof toward the upper and lower extremities thereof.

6. In combination: a vehicle drivers seat, and a pneumatic cushioning support for said seat, said support comprising a housing having a base, a skirt rising from said base and a top defining a central opening, a guide collar on said top around said opening, a seat support column slidable vertically in said collar and guided thereby; means mounting said seat upon the upper end of said column, and a dome-shaped diaphragm having a lower end sealed to said base, a skirt rising therefrom within said housing, and a top having a central portion supporting said column; a pneumatic cushioning chamber being defined within said diaphragm between its top and said base; said skirts having radially opposed portions thereof intermediate their upper and lower extremities bulged radially apart in the normally loaded condition of the diaphragm and defining between them an annular expansion space into which the diaphragm skirt is distended during relative downward movement of the diaphragm top into said cushioning chamber, and said skirts having radially opposed annular portions above and below said intermediate portions substantially engaging one another to close the upper and lower extremities of said expansion space in the normallyloaded condition of the diaphragm, the parts being so proportioned that the diaphragm skirt will be distended into full contact with the housing skirt below the diaphragm top and there will be a resultant rapid increase in air-cushion resistance to said downward movement, at a level of said downward movement sufficiently above said base to provide a pneumatic bottoming action absorbing heavy road shocks.

References Cited by the Examiner UNITED STATES PATENTS Re. 23,743 11/1953 Lambert et al 248-358 2,092,669 9/ 1937 Greve 248-400 2,650,648 9/1953 Nordmark et al 248-418 2,778,627 1/1957 Sands 267-1 2,880,782 4/1959 Conner 248-399 2,916,081 12/1959 Pinkel 297-216 3,007,660 11/1961 Rosan 248-20 CLAUDE A. LE ROY, Primary Examiner.

R. P. SEITTER, Assistant Examiner. 

1. A PNEUMATIC CUSHIONING SUPPORT COMPRISING: A HOUSING HAVING A BASE, A SKIRT RISING FROM SAID BASE AND A TOP DEFINING A CENTRAL OPENING; A GUIDE COLLAR ON SAID TOP AROUND SAID OPENING; A SEAT SUPPORT COLUMN SLIDABLE VERTICALLY IN SAID COLLAR AND GUIDED THEREBY; AND A DOME-SHAPED DIAPHRAGM HAVING A LOWER END SEALED TO SAID BASE, A GENERALLY CYLINDRICAL SKIRT RISING THEREFROM WITHIN SAID HOUSING, AND A TOP ADJACENT THE TOP OF SAID HOUSING AND HAVING A CENTRAL PORTION SUPPORTING SAID COLUMN; A PNEUMATIC CUSHIONING CHAMBER BEING DEFINED WITHIN SAID DIAPHRAGM BETWEEN ITS TOP AND SAID BASE; SAID SKIRTS HAVING RADIALLY OPPOSED PORTIONS THEREOF AT THEIR UPPER AND LOWER EXTREMITIES SUBSTANTIALLY IN CONTACT WITH ONE ANOTHER AND SAID HOUSING SKIRT HAVING AN ANNULAR PORTION THEREOF INTERMEDIATE ITS SAID UPPER AND LOWER END PORTIONS BULGED RADIALLY AWAY FROM THE OPPOSED INTERMEDIATE PORTION OF THE DIAPHRAGM SKIRT IN THE NORMALLY LOADED CONDITION OF THE DIAPHRAGM AND DEFINING THEREWITH AN ANNULAR EXPANSION SPACE INTO WHICH THE DIAPHRAGM SKIRT IS DISTENDED DURING RELATIVE DOWNWARD MOVEMENT OF THE DIAPHRAGM TOP INTO SAID CUSHIONING CHAMBER, THE PARTS BEING SO PROPORTIONED THAT THE DIAPHRAGM SKIRT WILL BE DISTENDED INTO FULL CONTACT WITH THE HOUSING SKIRT BELOW THE DIAPHRAGM TOP AND THERE WILL BE A RSULTANT RAPID INCREASE IN AIR-CUSHION RESISTANCE TO SAID DOWNWARD MOVEMENT, AT A LEVEL OF SAID DOWNWARD MOVEMET SUFFICIENTLY ABOVE SAID BASE TO PROVIDE A PNEUMATIC BOTTOMING ACTON ABSORBING HEAVY ROAD SHOCKS. 